Fix for #11503: when you send a transaction with value as 0x, you get a Bignumber error (#11996)

* Fix for #11503: when you send a transaction with value  as 0x, you get a
Bignumber error. Fix this by setting value to 0x0 is it's 0x.

Signed-off-by: Akintayo A. Olusegun <akintayo.segun@gmail.com>

* 1. Fix this in app/scripts/controllers/transactions/lib/utils.js
2. Make sure other non-hex non-valid strings for value return 0x0

Signed-off-by: Akintayo A. Olusegun <akintayo.segun@gmail.com>

* Linting Fixes.

Signed-off-by: Akintayo A. Olusegun <akintayo.segun@gmail.com>

* Instead of returning 0x0 for invalid hex values, throw a descriptive
error

Signed-off-by: Akintayo A. Olusegun <akintayo.segun@gmail.com>

* Unit tests.
Lint fixes.

Signed-off-by: Akintayo A. Olusegun <akintayo.segun@gmail.com>

* assert.throws takes a function

Signed-off-by: Akintayo A. Olusegun <akintayo.segun@gmail.com>

* Lint Fixes.

Signed-off-by: Akintayo A. Olusegun <akintayo.segun@gmail.com>

* Use standardized error message.

Signed-off-by: Akintayo A. Olusegun <akintayo.segun@gmail.com>

* remove fixHexValue
move code validating hex value to validateTxParams

Signed-off-by: Akintayo A. Olusegun <akintayo.segun@gmail.com>

* Change message displayed if hex string is invalid.

Signed-off-by: Akintayo A. Olusegun <akintayo.segun@gmail.com>

* Fixed missing second quote mark on message.

Signed-off-by: Akintayo A. Olusegun <akintayo.segun@gmail.com>

app/scripts/controllers/transactions/lib/util.js

@@ -197,6 +197,12 @@ export function validateTxParams(txParams, eip1559Compatibility = true) {
             `Invalid transaction value of "${value}": number must be in wei.`,
           );
         }
+
+        if (!value.match(/^0x[a-fA-F0-9]+$/u)) {
+          throw ethErrors.rpc.invalidParams(
+            `Invalid transaction value of "${value}": not a valid hex string.`,
+          );
+        }
         break;
       case 'chainId':
         if (typeof value !== 'number' && typeof value !== 'string') {